Duplicating process



1967 c. J. LEVINE ETAL 3,336,867

DUPLICATING PROCESS Filed June 4, 1965 FIG. I

INVENTORS. CHARLES J. LEVINE E REXFORD W. JONES United States Patent 3,33e,se7 DUPLICATHNG PROClE Charles J. Levine, Rochester, N .Y., and Rcxford W. Jones, Columbus, Ohio, assignors, by direct and mesne assignments, to Xerox Corporation, Rochester, NY, a corporation of New York Filed June 4, 1965, 591'. No. 461,238 4 Claims. (Cl. Mil- 468) ABSTRACT OF THE DISCLOSURE Multiple images are formed by simultaneously impressing a direct image onto an original sheet and a reversed image onto a transfer sheet, separating the transfer sheet from the original sheet, contacting the transfer sheet with a wax coated receiving sheet and applying suificient pressure to transfer at least a portion of the image from the transfer sheet to the receiving sheet. The simultaneous formation of the direct image and the reversed image is accomplished by applying pressure in image configuration to a sandwich comprising the original sheet, the transfer sheet and an image material sheet carrying pressure responsive imaging material on a face adjacent the transfer sheet. Multiple copies are formed by repeatedly transferring portions of the image on the transfer sheet to additional receiving sheets by application of pressure.

This invention relates to an imaging method and more particularly to a pressure transfer duplicating technique. l

Various techniques have been developed for making multiple copies of original documents by the transfer of a relatively dry imaging material or dry ink. One of the best known of these techniques is the production of carbon copies in a typewriter. Asidefrom the limited number of legible copies that can be made, this technique suffers from many other drawbacks. For example, the texture of the paper used in making copies must be extremely lightweight in order to transmit pressure for at least two or three copies. Also, in the event that more than a couple as spirit duplicating, mimeograph, and pressure pick off.

These techniques however, except for the latter, are prohibitive in cost if they are used to produce a relatively small number of duplicates of an original. The pressure pick off technique, more fully disclosed in German Patent No. 646,530 and US. Patent No. 3,122,094, requires bringing the original into contact with a wax-coated master and applying sufficient pressure to the sandwich so that sufficient ink is removed from the original and embedded into the master. Copies are then produced from the master by placing a receiving sheet in face'to-face contact with the master and applying pressure sufiicient to transfer at least a portion of the ink. Although the process is simple and inexpensive, it has inherent disadvantages. The selection of materials in this process is critical since the imaging material must be readily transferable without smudging and yet maintain a high enough optical density for a sufiicient number of copies. Also, the wax master creates a serious problem with the back transfer of wax to the original and copy sheets making it difficult to separate them and also to later write upon .them because of the wax coating on background areas. Moreover, since the imaging materials must be taken 3,336,867 Patented Aug. 22, 1967 from the original, a large portion of the material remains unavailable on the original. In addition, the image to be duplicated from the master is restricted to that shown on the original.

It is therefore an object of this invention to provide a novel duplicating process devoid of the above-noted disadvantages.

Another object of this invention is to provide a novel imaging technique.

Another object of this invention is to provide a pres sure duplicating process wherein the transfer sheet and copies can be modified without affecting the original.

Yet another object of this invention is to provide a simple and inexpensive pressure duplicating process.

Still another object of this invention is to provide a pressure transfer process capable of producing a plurality of copies having desirable optical density and readability.

Yet still another object of this invention is to provide a pressure duplicating process which does not adversely affect the background areas on the original and copy sheets.

Still a further object of this invention is to provide an improved receiving or copy sheet especially adapted for use in pressure duplicating.

The foregoing objects and others are accomplished in accordance with the present invention by providing an imaging method, comprising substantially simultaneously impressing a direct image onto the original and reverse image onto a second transfer sheet, separating said transfer sheet from the original, contacting the transfer sheet with a receiving sheet and applying thereto sufiicient pressure to transfer at least a portion of the image from the transfer sheet to the receiving sheet. In the process of this invention, the original, transfer sheet and imaging material sheets superimposed upon each other, in that order, are placed in a typewriter or another imaging impressing device. The imaging material sheet is positioned in the sandwich with the inked surface up in contact with the lower surface of the transfer sheet. Upon impressing the original, a reverse image is substantially simultaneously formed on the lower surface or back side of the transfer sheet which is in contact with the inked portion of the imaging material sheet. After removal of the sheets from the typewriter, the transfer sheet is placed in face-to-face contact with a receiving sheet and the two are run between a pair of pressure rollers or other pressure means, thereby transferring at least a portion of the material from the transfer sheet to the receiving sheet. This procedure is repeated until the desired number of copies are made or until the inked image on the transfer sheet is depleted. It is desirable for the receiving sheet to pull sufficient imaging material from the transfer sheet for good readability without detracting from its usefulness as copy paper wherein the background may be written on by various writing instruments. Best results were obtained when the receiving sheet comprised a paper substrate surface treated with a suitable wax formulation. The wax may be applied to the paper substrate in any suitable or well known manner and preferably during the manufacture of the paper itself. It has been found that at least ten copies of good readability can be made when using this type of receiving sheet, the copies having a substantially uniform and improved optical density.

The imaging material sheet can be any carbon paper suitable for pressure transfer duplicating. U.S. Patents 1,800,561; 2,589,306 and 2,820,717 disclose typical formulations which may be used in preparing these materials for the imaging material sheet. The imaging material sheet usually comprises at least a fifty percent concentration of pigment dispersed in a wax binder coated on a suitable substrate such as paper, cloth, polyethylene terephthalate or other polymeric films. Additional imaging materials suitable for use in this process may be found in copending application Ser. No. 451,960 filed in the United States Patent Oflice on Apr. 29, 1965.

Any light weight or medium weight bond paper, such as conventional pound to 22 pound, suffices as a transfer sheet for the process of the invention. However, the thinner and smoother the sheet and the more receptive it is to the imaging material, the better will the quality and density of the copies be. An especially suitable transfer sheet is the pound Scan-A-Master paper which is coated on two sides and super calendered. This paper is obtainable through the Columbia Ribbon and Carbon Manufacturing Company, Glen Cove, NY. It should be noted that any suitable coated or non-coated paper may be used as the transfer sheet.

In order to achieve the desired optical density, uniformity and readability, the copy or receiving sheet must exhibit sufiicient adhesive force to overcome the cohesive forces tending to hold the imaging material together on the transfer sheet. By treating ordinary bond weight paper with a water dispersed wax formulation, it is possible to perfect a copy or receiving sheet of this character. Since the imaging material normally has a wax-like binder or vehicle, the wax treated copy sheet surface (coating up to about 10 microns thick) is miscible with and adheres to the imaged areas. Care must be taken not to use too much wax on the copy paper as it is undesirable to pull too much imaging material from the transfer sheet per single transfer. Moreover, too much wax may cause some difficulty if the paper is to be suitable for other purposes such as writing on background areas with pencil or pen. A concentration of about 2% to solid wax dispersed in water and applied'to a final wax thickness of about 2 to 10 microns has been found to be preferred and gave superior results in the present process.

The particular wax used depends upon such factors as the imaging material components and the substrate to be treated. Typical waxes suitable for surface treatment of copy paper are paraffin waxes, microcrystalline waxes, low molecular weight polyethylenes, beeswax, and mixtures thereof. Of course, any other suitable wax may be used if desired. In preparing the water dispersed wax, it is preferable to add from about .001 to 1 part by weight of at least one suitable detergent to the water before adding the wax to the liquid mix. This contributes to the wettability of the paper and also assists in defoaming, emulsifying and dispersing. Typical detergents are Triton X100 (an alkyl phenoxy polyethoxy ethanol composition) available from Rohm & Haas Company, oleic acid and Tween 20 (polyoxyethylene sorbitan monolaurate) and Tween 40 (polyoxyethylene sorbitan monopalmitate) available from Atlas Powder Company, or any other suitable emulsifying agents. The paper can be treated with the water dispersed wax in any convenient manner and preferably during the manufacture of the paper. Typical methods for doing so are by incorporation into the paper pulp itself, by size press, spraying, reverse roll coating, wire-wound rod, air knife and trailing blade. The water or other liquid carrier is allowed to evaporate, thereby leaving a layer of wax of up to about 10 microns thick. If the thickness of the wax layer exceeds this limit, difficulty is encountered in making a plurality of copies since too much image material is pulled from the transfer sheet per transfer. In addition, smudging and other disadvantages result when using a coating above about 10 microns.

The process and system of this invention will be further defined in relation to the accompanying drawing. The embodiments illustrated herein are preferred embodiments, however; they are to be considered as illustrative only and not limiting.

In the enclosed drawing, FIG. 1 is a perspective view illustrating the position of the various paper sheets sandwiched together in the present invention; and

FIG. 2 is a sectional view illustrating a transfer and transfer means utilized to transfer the image from the transfer sheet to a pressure sensitive receiving or copy sheet.

Referring first to FIG. 1, original sheet 1 is positioned or superimposed above transfer sheet 2 and transfer sheet 2 is positioned immediately above imaging material sheet 3. The original sheet 1 and transfer sheet 2 may be any conventional or suitable paper, however, for the purposes of this invention, best results were used when imaging material sheet 3 has an inked surface comprising at least a 50% concentration of pigment dispersed in a wax binder or other suitable binders.

As noted above, transfer sheet 2 may also be a wax treated paper. The ink on imaging material sheet 3 may be a wax suspension or solution, or may be similar compositions to those described in the United States patents above listed. It is important that the inked surface 14 be in direct contact with the surface 15 of transfer sheet 2. Upon impressing an image 4 on the original sheet 1, the pressure applied to impart the image on the original sheet 1 simultaneously causes a reverse image to be formed on the surface 15 of transfer sheet 2. The reverse image 6 formed on transfer sheet 2 comprises an inked portion from ink surface 14. Illustrated in the drawing is the relative position of the sheets in the sandwich structure, and shown after the image has been imparted to the original sheet 1 and impressed or transferred to transfer sheet 2. The ink-void portion on imaging sheet 3 is shown in an exaggerated manner for purposes of clarity.

Also shown is the step of separating original 1, transfer sheet 2, and imaging material sheet 3 after the image has been impressed upon the sandwich structure formed by these superimposed members. It should be noted that reverse image 6 is formed on the back side 15 of transfer sheet 2 which is in face-to-face contact with the imaging material on sheet 3 while the direct image is simultaneously made on the original. After separating original 1, additional information may be included on the transfer sheet 2 simply by impressing it against imaging material sheet 3. The original 1 may be retained and may be used independent of copies made from transfer sheet 2. It is an important feature of the present invention that original sheet 1 is not degraded in any way, may be utilized as any other original, and has all the advantages of any conventionally typed original.

In FIG. 2, the image laden transfer sheet 2 is, after separation from the sandwich structure, placed in faceto-face contact with a pressure sensitive receiving sheet 10 and pressure is applied via rollers 7 to thereby transfer a portion of the image 6 from transfer sheet 2 to a sheet receiving or copy sheet 10. The pressure is controlled so as to transfer just that desired portion of ink image 6 in successive transfer steps.

As noted earlier in this disclosure, receiving sheet 10 preferably has a wax coating 9 positioned on substrate 11 thereon of up to about 10 microns thick. It is critical to this invention that this thickness not be exceeded. The image 6 is then transferred so that a portion of the wax ink making up image 6 is transferred to each successive receiving sheet to obtain the number of copies desired. In the embodiment illustrated herein, transfer sheet 2 and receiving sheet 10 are positioned between rollers 7 and 8 in such a manner that sufficient pressure is exerted between the rollers to transfer at least a portion of the ink image 6 from the transfer sheet 2 to the receiving sheet 10. For illustrative purposes, the image portion 16 remaining on the transfer sheet 2 after transfer of portion 12 to receiving sheet 10 is shown to be approximately half the thickness of original image thickness 6. Realistically, however, portion 16 will become thinner as more copies are made. The step illustrated in FIG. 2 may be repeated with additional sheets similar to pressure or copy sheet 10 until the imaging material 6 has been depleted from transfer sheet 2 or until the desired number of copies are obtained.

The following examples will further define preferred embodiments of the present invention. Parts and percentages are by weight unless otherwise indicated.

Examples I and II About 0.2 cc. of Triton X-lOO (an alkyl phenoxy polyethoxy ethanol composition) available from Rohm & Haas Company is stirred into 85 cc. of tap water at 25 C. Next, 15 cc. of Alwax 253 A, an aqueous emulsion of 40% crystalline paraflin wax, is added with mechanical stirring for about 1 hour at moderate speed. The water dispersed wax is sprayed on each of sheets of bond weight paper using an air brush to a thickness of up to about 10 microns and preferably about 2 to 10 microns.

Two sheets of bond weight paper are placed over an A & W carbon sheet (carbon paper available from Interchemical Corporation, Ault and Wiborg Carbon and Ribbon Division) and inserted into a manual typewriter. The carbon paper is positioned ink side up in contact with the second sheet of bond paper. After typing, the original has the typed-on image while the second sheet of bond paper now has a reverse image on its back side. The second (transfer) sheet is then placed in face-to-face contact with a sheet of (previously defined) treated bond paper and passed between a pair of steel rollers set to apply 200 pounds per lineal inch in the manner similar to that shown by FIG. 2. of the drawing. The same reverse image is then used to make copies on nine remaining treated receiving sheets.

In a second operation method the duplicating method is repeated, but untreated paper is used as receiving sheets in place of the treated copy paper. It is noted that there is an average increase of 50% in the optical density of the images transferred to the treated copy paper over that of the untreated copy paper. Also, the ability of the background on the treated and untreated copy sheets to receive fountain and ball-type writing inks appears about the same.

Example Ill Six sheets of bond weight paper and five sheets of conventional commercial carbon paper, each of the latter being spaced between a pair of the former, are inserted in the same typewriter used in above Examples I and II. After typing, the original and carbon copies are compared to those in Example I. All of the copies pro duoed in Example I are substantially superior in readability and optical density to the last three copies made via the process of this example and noticeably better in quality than the first and second copies made by the process of the present example.

Other materials suitable for use in the ink or wax layers may be used to enhance or otherwise effect the properties of these layers. In addition, other steps than those specifically defined above may be used together with those recited to add features further desired.

Although specific components are described in the above examples, other materials and transfer agents may be used with similar results. Various modifications will become apparent to those skilled in the art upon a reading of this disclosure; these are intended to be encompassed within the scope of this invention.

What is claimed is:

1. An imaging process comprising:

(a) providing a transfer sheet sandwiched between an original sheet and an imaging material sheet, said imaging material sheet carrying pressure responsive imaging material on a face adjacent said transfer sheet;

(b) applying pressure in image configuration to the outer face of said original sheet sufficient to substantially simultaneously image said original sheet and transfer said pressure responsive imaging material in image configuration to the face of said transfer sheet in contact with said imaging material;

(c) separating said imaging material sheet and said original sheet from said transfer sheet;

(d) placing said transfer sheet in face-to-face contact with the waxed surface of a receiving sheet, said waxed surface having a thickness up to about 10 microns; and

(e) applying sufiicient pressure to at least one face of said transfer and said receiving sheets to thereby transfer a portion of said imaging material from said transfer sheet to said waxed surface of said receiving sheet.

2. A process according to claim 1 including the steps of repeatedly transferring portions of said imaging material from said transfer sheet to additional receiving sheets by applying sufficient pressure to transfer a portion of said imaging material to said receiving sheets.

3. A process according to claim 1 wherein said waxed surface comprises a wax composition selected from the group consisting of paraffin wax, microcrystalline wax, beeswax, and mixtures thereof.

4. A process according to claim 1 wherein said waxed surface is from about 2 to about 10 microns thick.

References Cited UNITED STATES PATENTS 680,637 8/ 1901 Brown.

FOREIGN PATENTS 646,530 6/ 1937 Germany.

WILLIAM B. PENN, Primary Examiner. ROBERT E. PULFREY, Examiner. J. A. BELL, Assistant Examiner. 

1. AN IMAGING PROCESS COMPRISING: (A) PROVIDING A TRANSFER SHEET SANDWICHED BETWEEN AN ORIGINAL SHEET AND AN IMAGING MATERIAL SHEET, SAID IMAGING MATERIAL SHEET CARRYING PRESSURE RESPONSIVE IMAGING MATERIAL ON A FACE ADJACENT SAID TRANSFER SHEET; (B) APPLYING PRESSURE IN IMAGE CONFIGURATION TO THE OUTER FACE OF SAID ORIGINAL SHEET SUFFICIENT TO SUBSTANTIALLY SIMULTANEOUSLY IMAGE SAID ORIGINAL SHEET AND TRANSFER SAID PRESSURE RESPONSIVE IMAGING MATERIAL IN IMAGE CONFIGURATION TO THE FACE OF SAID TRANSFER SHEET IN CONTACT WITH SAID IMAGING MATERIAL; (C) SEPARATING SAID IMAGING MATERIAL SHEET AND SAID ORIGINAL SHEET FROM SAID TRANSFER SHEET; (D) PLACING SAID TRANSFER SHEET IN FACE-TO-FACE CONTACT WITH THE WAXED SURFACE OF A RECEIVING SHEET, SAID WAXED SURFACE HAVING A THICKNESS UP TO ABOUT 10 MICRONS; AND (E) APPLYING SUFFICIENT PRESSURE TO AT LEAST ONE FACE OF SAID TRANSFER AND SAID RECEIVING SHEETS TO THEREBY TRANSFER A PORTION OF SAID IMAGING MATERIAL FROM SAID TRANSFER SHEET TO SAID WAXED SURFACE OF SAID RECEIVING SHEET. 